An earlier version of the Mona Lisa?

The Swiss-based Mona Lisa Foundation believes they have proven that Leonardo da Vinci painted an earlier version of the Mona Lisa.

Known as the Isleworth Mona Lisa, the canvas painting is larger the original Mona Lisa, as well being brighter and with a different background. It appears to depict the famous lady in the Mona Lisa portrait, which is thought to be Lisa Del Giocondo, the wife of a wealthy Florentine merchant. Experts have debated if the work has also been an original Da Vinci work, but the Mona Lisa Foundation believes that its scientific tests prove that it was made about ten years earlier than the masterpiece.

The Isleworth Mona Lisa has been known to experts for years, but they remain divided on whether the painting is by Leonardo or whether it shows the same woman.

Art historian Stanley Feldman, who wrote Mona Lisa: Leonardo’s Earlier Version for the foundation, said “So far, not one scientific test has been able to disprove that the painting is by Leonardo. We have used methods that were not available to Leonardo 500 years ago.”

The foundations claims it was painted a decade before the famous portrait of Lisa Gherardini del Giocondo, who is thought to have sat for the painting which now sits in the Louvre between 1503 and 1506, based on regression tests, mathematical comparisons and historical and archival records.

“When we do a very elementary mathematical test, we have discovered that all of the elements of the two bodies — the two people, the two sitters — are in exactly the same place,” Feldman added. “It strikes us that in order for that to be so accurate, so meticulously exact, only the person who did one did the other … It’s an extraordinary revelation in itself, and we think it’s valid.”

Martin Kemp, emeritus professor of the History of Art at the University of Oxford, is skeptical of the analysis. “The Isleworth Mona Lisa miss-translates subtle details of the original,” he says, “including the sitter’s veil, her hair, the translucent layer of her dress, the structure of the hands. The landscape is devoid of atmospheric subtlety. The head, like all other copies, does not capture the profound elusiveness of the original.”

Kemp also believes the evidence from the scientific testing does not suggest that this is an earlier work by Leonardo. “The infrared reflectography and X-ray points very strongly to its not being by Leonardo,” he explains. “The images produced by infrared reflectography and X-ray are not all characteristic or what lies below Leonardo’s autograph paintings. We know that changes were made in the Louvre painting. The Isleworth picture follows the final state of the Louvre painting. It does not therefore precede the Louvre painting.”

The Isleworth Mona had belonged with a British family for over 150 years, before being sold to art dealers in the 20th century. Since 1979 the painting has been left half-forgotten in a vault.